Rangers manager Walter Smith has agreed to work at the club without a contract until a buyer can be found. Photograph: Craig Halkett/PA

Rangers fans concerned about the club's future were handed a boost today when the chairman, Alastair Johnston, revealed there has been worldwide interest from people seeking to buy the club. It also emerged that the manager, Walter Smith, would continue to work without a contract until a buyer is found.

David Murray's majority stake in Rangers remains for sale as Johnston hunts for much-needed fresh investment in a club that is £31m in debt and the subject of scrutiny from Lloyds. "There are individuals who have demonstrated an interest and ability to move towards participation in ownership," Johnston said. "I have encouraged them to do that. We are in discussions with a lot of those fans throughout the world."

Johnston said his focus has been on finding a single or small group of owners for Rangers rather than a fans-led conglomerate. The latter scheme was likened by the chairman to a club buying a player before discovering they could not pay his wages. "I am sceptical," said Johnston of a Barcelona-type membership scheme.

Speaking at the club's AGM, Johnston said neither Lloyds nor Murray had named a price for the latter's 92% stake. Rangers are committed to wiping £1m from their debt each year but selling the naming rights to the stadium would not be considered. "Ibrox is non-negotiable," Johnston insisted.

The chairman added: "The bank said to us 'we want you to operate within your means. We are not going to let you, as before, speculate to accumulate. That contributed to your debt situation.'"

Smith and his coaching team will not sign new contracts next month. "Walter, [the assistant] Ally McCoist and [coach] Kenny McDowall have agreed to work without contracts to protect the club from having a management team that new owners might not want," said Johnston. Smith, meanwhile, conceded "stagnation" is a problem within his playing squad.

Hearts could escape action from the Scottish Football Association in the short-term at least after the tunnel fracas that followed Sunday's defeat at Hamilton. Two Hearts players were dismissed during the game and another two were shown red cards afterwards over the tunnel incident. The SFA could decide the affair was suitably handled by the referee, David Somers. Hearts players have collected 18 red cards in as many months, a matter that will be of more interest to the SFA.